Protoplast Fusion in the Genus Medicago and Isoenzyme Analysis of Parental and Somatic Hybrid Cell Lines

Leaf mesophyll protoplasts of Medicago arborea (2n = 32) were electrofused with cell suspension and/or callus protoplasts of Medicago sativa. Heterokaryons were identified in agarose beds by their dual fluorescein isothiocianate—chlorophyll fluorescence and their coordinates were recorded. Hybrid minicalli were manually picked up and grown first in nurse culture and then in callus induction medium. Hybrid nature of the selected calli was confirmed by isoenzyme analyses. In order to verify whether morphogenesis of somatic hybrid calli was affected by cell incompatibility, mesophyll and cell suspension protoplasts, derived from the same plant of M. sativa with high embryogenic capacity, were fused. Only callus tissues derived from mesophyll protoplasts retained the highly embryogenic character of the M. sativa genotype, while hybrid cell lines were non-morphogenic and showed isoenzyme patterns similar to tissues derived from cell suspension protoplasts. The achievement of somatic hybrid plants in the genus Medicago is discussed.     

Effect of silicon on the eutectic carbides in as-heated M2 high speed steel

The effect of silicon on the eutectic carbides in as-heated M2 high speed steels is investigated by using optical microscope, scanning electron microscope, energy dispersive spectrometer and X-ray diffraction analysis. The high speed steel ingots with different silicon additions are produced by electroslag remelting process (the mass content of silicon is 0.3%, 0.8%, 1.6% and 2.4%, respectively). The ingots are annealed at 780 ℃ for 10 h and heated at 1 165 ℃ for 2.5 h. The results show that the eutectic carbides distributed in the dendrites with continuous or semi-continuous net-shape in the as-annealed ingots. The eutectic carbides change from lamellar-like M2C to herringbone-like M6C with the increase of silicon content. After 2.5 h heating at 1 165 ℃, the lamellar-like M2C decomposes into granular M6C and MC, and the size of granules in M2 high speed steel ingot with 0.8%Si addition is smaller than that in the 0.3%Si. Whereas herringbone-like M6C is unchanged during heating treatment, and coarse primary blocky carbides which are harmful for properties still exists after the deformation.     

云杉、樟子松苗木高生长预测

本文采用灰色系统的GM(1,1)模型,对雪岭云杉和樟子松两苗木的高生长进行了预测,获得了较高精度。经分析认为用GM(1,1)模型预测以上两树种苗木高生长是可行的。     

变叶海棠（Malus toringoides）X陇东海棠（M.kansuensis）研究

对兼性无融合生殖种变叶海棠(3x)和陇东海棠(2x)的杂种实生苗进行了鉴别和矮化效应预测。结果表明,4x 杂种苗占65.2%,3x 母体苗占34.8%。杂种苗的酶谱可分为偏母型、互补型和突变型。互补型酶谱杂种苗的平均根皮率和叶片过氧化物酶活性显著高于偏母型酶谱杂种苗。选出的7株杂种单株,酶谱均属于互补型或突变型,表明陇东海棠的特征酶带20和21与其矮化效应有关。利用过氧化物酶同工酶谱可对该组合杂种苗的矮化效应作初步预测。     

苜蓿旱作栽培品种比较试验(1988～1990)

本文介绍了在乌鲁木齐冬季严寒,夏季酷热,年降水量230mm左右,在旱作栽培的条件下,进行了6个苜蓿品种的正规比较试验。历时三年,以产量、草质、越冬率、生长速度及再生等性状比较,以图牧二号紫花苜蓿(Medicago staiva L)阿勒泰杂花苜蓿(M.varia Martyn)石河子杂花苜蓿(M.varia Martyn)表现最好,其次是贝维尔杂花苜蓿(M.varia Martyn)。     

M增产素对小麦抗旱性的影响

通过Ｍ增产素对小麦进行浸种和抽穗开花期喷洒处理，重点研究了对小麦后期水分生理指标、叶绿素含量、外渗电导值以及产量等的影响．结果表明，处理明显地改善了小麦的水分状况、降低了电解质外渗率，有明显的保绿作用，防止叶片早衰、增产效果显著。     

Tracing sources of soil nitrate using the dual isotopic composition of nitrate in 2 M KCl-extracts

Soils comprise a critical interface between the atmosphere, lithosphere, hydrosphere and biosphere, and play a major role in the cycling of nitrogen (N), an element crucial to plant growth. Isotope techniques constitute a powerful tool to study the origin and fate of N compounds (e.g. NO₃⁻) within the environment including soils. The objective of our study was to test the usefulness of the isotope composition of soil NO₃⁻ extracted with 2 M KCl (soil NO₃) as a tool to investigate the origin and fate of NO₃⁻ in the environment. Specifically issues related to repeat extractions, crop type, length of fertilization, and soil depth were addressed. Soils from four contrasting agricultural management regimes were sampled. Within the relatively confined study area (4 ha), the isotopic compositions of soil NO₃ differed markedly due to management treatments (up to 6 and 17‰ for δ¹⁵N and δ¹⁸O, respectively), but were repeatable among replicate plots (±1‰). Differences in both δ¹⁵N and δ¹⁸O values were observed between legume and non-legume treatments, as well as fertilized versus non-fertilized treatments, which were larger than the variability observed between replicate plots. Differences in the isotopic composition of extractable soil nitrate were not limited to the surface layer, but also occurred within deeper soil layers. This study indicates that the analysis of the natural abundance stable isotope composition of soil NO₃ may provide a promising additional tool for tracing the origin and fate of NO₃⁻ in the soil zone.     

牛支原体肺炎流行RT-PCR方法的初步诊断

设计5对引物,对山东某一牛交易市场采集的64份鼻腔棉拭子样品进行了病原学检测。对所有样品进行差异脲原体、牛支原体、牛生殖道支原体、牛眼支原体和牛传染性胸膜肺炎(CBPP)PCR病原学检测,PCR产物连接T载体测序。PCR结果显示,牛支原体阳性样品7份,牛生殖道支原体、牛眼支原体和牛丝状支原体全部为阴性;测序结果显示,所测样品核酸序列与牛支原体和无乳支原体核酸序列都具有很高的同源性。对核酸序列进行遗传进化树分析表明,相对于无乳支原体而言,所测核酸序列与牛支原体物种具有更近的遗传距离。     

鸡传染性支气管炎病毒SX-H09株膜蛋白基因的克隆及序列分析

对鸡传染性支气管炎病毒(IBV)陕西分离株SX-H09株膜蛋白(M)基因进行克隆和序列分析.根据GenBank发表的IBV基因序列设计1对特异性引物,RT-PCR扩增IBV M基因片段,并进行克隆、序列测定和分析.结果表明,SX-H09株M基因全长为678 bp,编码225个氨基酸.同源性比较可知,SX-H09株M基因...